The pumping unit, also known as a “kowtow machine”, is a type of mechanical equipment for oil mining, which pumps oil from the well by pressure. The conventional walking beam pumping unit is powered by the cooperation of a motor and a reducer. However, the lubricating oil and the drive belt of the reducer need to be replaced regularly and both the reducer and the drive belt will increase failure rate; moreover, the conventional pumping unit is not energy saving with high motor power, small change of output power and largely increased production cost.